1. Field
The present invention relates to a feature point used to localize an image-based robot and build a map of the robot, and, more particularly, to a method of extracting and matching an image patch of a three-dimensional (3D) image, which is used as the feature point.
2. Description of the Related Art
Generally, a robot is a mechanism to perform a motion resembling an action of a human being using an electrical or magnetic operation. Recent robots have been utilized in various applications due to the development of sensors and controllers. For example, a robot can be used for housework, public service, or a conveying robot or worker-assisting robot on a production line. For the robot to move under its own self-control, it is necessary to simultaneously perform a localization process to recognize its position without preliminary information on a peripheral environment and a map building process to build a map from the information on the environment. This overall process is called simultaneous localization and map-building (SLAM).
The SLAM is a technology to acquire an image through an all-direction view camera, build a map in real time, and recognize a position. The SLAM is used as an appropriate substitute for indoor localization. However, the SLAM finds a feature point from the acquired image and extracts an image patch having several pixels around the feature point, i.e., extracts an image patch of a 3D image with a predetermined size (15×15 pixels) only from the image itself. For this reason, when a spatial relationship between the camera and the feature point (3D position) changes due to the movement of the camera, the size and direction of the feature point in the image change, with the result that several errors are included in the position of the robot. Thus, it is not possible to accurately localize the robot and build a map of the robot.